diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..33b0505
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,20 @@
+[run]
+branch = True
+parallel = False
+source =
+    src
+
+[report]
+show_missing = True
+skip_covered = False
+exclude_lines =
+    pragma: no cover
+    if __name__ == .__main__.:
+    # Add project-specific exclusions as needed
+
+omit =
+    tests/*
+    **/__init__.py
+
+[html]
+directory = htmlcov
diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
new file mode 100644
index 0000000..0c48f32
--- /dev/null
+++ b/.github/workflows/coverage.yml
@@ -0,0 +1,84 @@
+name: Code Coverage
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    env:
+      # Probably unnecessary, if we install the code as a package
+      PYTHONPATH: src
+      # Set your thresholds here
+      OVERALL_COVERAGE_FAIL_UNDER: "60"
+      DIFF_COVER_FAIL_UNDER: "70"
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # needed for diff-cover to compare against main
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: "pip"
+
+      - name: Install test deps
+        run: |
+          python -m pip install --upgrade pip
+          pip install coverage diff-cover
+
+      - name: Prepare for tests
+        run: sh prepare_for_tests.sh
+
+      - name: Run unit tests with coverage
+        run: |
+          pip install -e ".[dev]"
+          coverage run --rcfile=.coveragerc --source=src -m unittest discover tests
+          coverage report -m --fail-under="${OVERALL_COVERAGE_FAIL_UNDER}"
+          coverage xml -o coverage.xml
+          coverage html -d htmlcov
+
+      - name: Diff coverage for PR changes
+        if: ${{ github.event_name == 'pull_request' }}
+        run: |
+          # Ensure main is available for comparison
+          git fetch origin main:refs/remotes/origin/main
+
+          # Compute coverage on changed lines only and fail if under threshold
+          diff-cover coverage.xml \
+            --compare-branch=origin/main \
+            --fail-under="${DIFF_COVER_FAIL_UNDER}" \
+            --html-report diffcov.html > diffcov.txt || RC=$?
+
+          # Attach a concise summary to the job summary
+          {
+            echo "## Diff Coverage Summary"
+            echo ""
+            echo "\`diff-cover --fail-under=${DIFF_COVER_FAIL_UNDER}\` against origin/main"
+            echo ""
+            echo '```'
+            cat diffcov.txt
+            echo '```'
+          } >> "$GITHUB_STEP_SUMMARY"
+
+          # Exit with diff-cover status if it failed
+          exit ${RC:-0}
+
+      - name: Upload HTML reports
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-reports
+          path: |
+            htmlcov/
+            diffcov.html
+            coverage.xml
+          if-no-files-found: ignore
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index b90ad62..b562c35 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ target
 build
 dist
 gen
+.coverage
diff --git a/README.md b/README.md
index de72ab6..215f387 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,8 @@ This library is released under the Apache V2 License.
 
 Read the [Documentation](https://lionweb.io/lionweb-python)
 
+We support Python 3.9 to 3.13
+
 ## Linting
 
 ```
@@ -47,4 +49,15 @@ twine upload dist/*
 ```
 sh prepare_for_tests.sh # to be run just once
 PYTHONPATH=src python -m unittest discover tests
+```
+
+You can measure coverage like this:
+```
+PYTHONPATH=src coverage run -m unittest discover tests
+```
+
+And then generate a report with:
+```
+coverage html                                         
+# report generated under htmlcov/index.html
 ```
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index 41f7e00..b78de1f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,8 +18,16 @@ description = "A Python package for working with LionWeb"
 readme = "README.md"
 authors = [{ name = "Federico Tomassetti", email = "federico@strumenta.com" }]
 license = { file = "LICENSE.txt" }
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
     "requests",
-    "pydantic"
+    "pydantic",
+    "typing_extensions>=4.8",
+]
+
+[project.optional-dependencies]
+dev = [
+    "coverage",
+    "diff-cover",
+    "testcontainers>=4.0",
 ]
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
index d4ceeee..6ae0aba 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,6 +10,7 @@ certifi==2025.1.31
 cfgv==3.4.0
 charset-normalizer==3.4.1
 click==8.1.8
+coverage==7.10.6
 decorator==5.2.1
 distlib==0.3.9
 distro==1.9.0
@@ -47,6 +48,7 @@ mypy==1.15.0
 mypy-extensions==1.0.0
 nh3==0.2.20
 nodeenv==1.9.1
+numpy==2.0.2
 packaging==24.2
 parso==0.8.4
 pathspec==0.12.1
diff --git a/tests/docker/Dockerfile b/tests/docker/Dockerfile
index 085d692..fb4fcd7 100644
--- a/tests/docker/Dockerfile
+++ b/tests/docker/Dockerfile
@@ -1,5 +1,5 @@
 FROM node
-ARG lionwebServerCommitId=64aeb0de69bbb39626e7f107ba26eb0061063c9c
+ARG lionwebServerCommitId=e6549d62a4728a91e1ca31afb9b5341b47b88c99
 RUN mkdir lionweb-server
 WORKDIR lionweb-server
 RUN git init